Digital up converters (“DUCs”) and digital down converters (“DDCs”) are well-known circuits used in signal processing. Conventionally, a modulated digital input signal is up-converted prior to being input to a digital-to-analog converter (“DAC”) of a DUC, and, conventionally, a modulated analog input signal is input to an analog-to-digital converter (“ADC”) of a DDC for subsequent digital down conversion by such a DDC.
An overall bandwidth of a multi-carrier signal is conventionally proportional to a sum of the bandwidths of component carriers of such multi-carrier signal, namely a passband of such component carriers. Moreover, such a passband of component carriers may be larger or smaller than a sampling frequency, fs, divided by the number of component carriers, M. Such a non-native resolution bandwidth fs/M is generally referred to herein “an arbitrary passband bandwidth”.
Accordingly, it is desirable and useful to provide an M-path filter for multi-channel or multi-band signals that is adjustable to an arbitrary passband bandwidth of component carriers.